Amanda Knox and her former Italian boyfriend will make a last attempt on Monday to persuade the court hearing their appeals that they had nothing to do with the 2007 murder of Knox's then-flatmate, the British student Meredith Kercher.

Members of the victim's family will fly into Perugia for the keenly awaited outcome, but were expected to arrive too late to hear the final pleas of Kercher's convicted killers. Their presence, just feet away from the relatives of the two appellants, will add an extra layer of tension to a case already brimming with drama and expectation.

The Kerchers' legal representatives at the appeal have unequivocally aligned themselves with the prosecution's case that Knox slashed the British student's throat as she was held immobile by Knox's then boyfriend, Raffaele Sollecito, and Rudy Guede, a small-time drugs trafficker from the Ivory Coast. But the family's lawyer, Francesco Maresca, told the Guardian: "Just as they respected the verdict at the trial, so they will respect the outcome of the appeal."

Knox attended mass on Saturday in the prison near Perugia where she has been held for almost four years since her arrest. The prison chaplain, Father Saulo Scarabattoli, said she had played guitar during the service, as she did every weekend. "You can imagine how she is," he said. "But Amanda evinces great strength and hope."

In June, two independent court-appointed experts dismissed as unreliable key forensic evidence against the University of Washington student and her former lover. Since then, a widespread expectation has built up in the US that their appeals will be upheld.

In Italy, public opinion – once largely hostile to Knox, seen as an angel-faced killer – has become more divided. One of the country's most widely read magazines, Oggi, has campaigned to draw attention to the weaknesses in the prosecution case. And an MP for Silvio Berlusconi's party, Rocco Girlanda, who visited her on Saturday, has become an important advocate of her cause.

But what little evidence there is suggests most Italians believe Knox and Sollecito were involved in Kercher's murder. In a viewers' poll conducted by Sky Italia after the prosecution wound up its case, only 27% of respondents thought the couple were innocent.

If that balance of sentiment is reflected among the six lay judges who will help to reach Monday's decision, it could tell against Knox and her former boyfriend, even if the two professional judges are convinced of their innocence. The court president, Claudio Pratillo Hellmann, has two votes to cast; the other full-time judge, Massimo Zanetti, one. But the lay judges also have a vote each, and can therefore decide the outcome.

According to a local paper, Corriere dell'Umbria, clandestine bookmakers – betting is a state monopoly in Italy – were so uncertain of the outcome that many were refusing to take bets. Those who did were offering identical odds of 2 to 1 against both a conviction and an acquittal. The shortest odds – evens on a reduction of the appellants' sentences.

Whether that would allow Knox and Sollecito to walk free would depend on how much was lopped off their sentences and the amount of remission they were granted. In any event, both the prosecution and defence can opt for a final appeal to the court of cassation in Rome, though it normally rules only on points of law.

Knox, who arrived in Italy less than a month before the killing, was sentenced to 26 years at the trial two years ago. Sollecito, who had known Knox for just six days, was given a 25-year sentence.

Their lawyers have argued Kercher was killed by Guede alone during a break-in. They have poured scorn on the prosecutors' theory of a sex game that got out of hand.